Burglar alarm



Feb. 24, 1925. 1 1,527,591

' J. F. LAWRENCE BURGLAR ALARM Filed Oct. 6, 192 2 M aw Patented Feb. 24, 1925 UNITED STATES JAY F. LAWRENCE, OF CHICAGO, ILLINOIS.

BURGLAR ALARM.

Application filed October 6, 1922. Serial No. 592,704.

To all whom it may concern:

Be it known that I, JAY F. LAWRENCE, a citizen of the United States, and a resident of the city of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful. Improvements in a Burglar Alarm; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the numerals of reference marked thereon, which form a part of this specification.

This invention refers to a combined closure fastener for doors and a burglar alarm operated by the closure fastener when an attempt is made to force the door open against the pull of the fastener, and has for its ob ject to provide certain improvements in the same, as hereinafter more definitely will be pointed out and claimed.

The invent-ion (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 shows an elevation of a door with the device of this invention installed thereon.

Figure 2 is an enlarged elevation of the device of this invention in operating position.

Figure 3 is a fragmentary elevation of the bell used in this invention showing the striking mechanism.

Figure 4 is a rear elevation of the device of this invention.

As shown on the drawings:

A description of the device as installed on an ordinary door follows. In Figure 1 the numeral 1 refers to an ordinary door, and the door jamb is marked 2. The device consists of a plate 3 mounted on the door with an ordinary mechanically operated bell '1 thereon, another plate 5 mounted on the door jamb carrying a chain 6 with alocking member 7 to engage in slots 8 and 9 in the plate 3 to hold the door either closely locked or to permit its opening a few inches. This locking member 7 cannot be disengaged from the slots except when the chain is slackened by completely closing the door. The back view of the plate 3 shown in Figure 4 shows will place the locking member 7 in one of the slots thereby preventing the door from opening more than an inch or so. The looking member will bear against the wire corresponding to the notch used. If an attempt is made to force the door open against the pull of the chain the wire will be sprung causing the bell operating mechanism to operate, calling attention to the fact that someone is attempting to get in through the door. The bell ringing would naturally discourage the burglar at the same time it calls the housekeepers attention to the door.

It is of course to be understood that this invention is equally applicable to bar latches and similar locks, and that visible as well as audible signalling apparatus can be used as a part of the combination.

I claim as my invention:

A door securing device comprising a symmetrical plate having long and short slots therein, a spring actuated bell centrally dis posed thereon above said slots, at second plate, a chain secured thereto, a member on the free end of said chain adapted to engage through either of the slots in the first mew tioned plate, and separate members disposed across the extremities of both slots and joined together above the slots to cause actuation of said bell when forcibly contacted by the member on the free end of the chain.

In testimony whereof I have hereunto subscribed my name in the presence of two subscribing witnesses.

JAY F. LAWREN O. Witnesses:

CARLTON HILL, OSCAR ,HARTMANN. 

